/Engine/Source/Runtime/GeometryCore/Public/DynamicMesh/DynamicVertexAttribute.h
Allocate a new compact copy of the attribute layer, optionally with a different parent. Default implementation does a full copy and then compacts it, usually derived class will want to override this with a more efficient direct compact copy implementation
virtual [TDynamicAttributeBase](API\Runtime\GeometryCore\DynamicMesh\TDynamicAttributeBase)< ParentType > * MakeCompactCopy ( const [FCompactMaps](API\Runtime\GeometryCore\Util\FCompactMaps) & CompactMaps, ParentType * ParentIn ) const